vacuum analyze corrupts database?

Our server is running vacuum analyze every night. We had problems with this
before, when we used v.7.2.1. Now with v.7.3.2 it appears again.
After nightly maintenance application isn't functioning. It looks that
corruption occurs (at least) on one table. Here's what I have in psql
session.

-- This query works fine, I copy the partial output here. --
syncdb=# SELECT nl_obj_url FROM note_links_aux ;
... ... ...
 sync:///FUNCTREE/ReuseMethodology/RTL_Coding
 sync:///Projects/KB
 sync:///FUNCTREE/ReuseMethodology/RTL_Coding
 sync:///FUNCTREE/ReuseMethodology/RTL_Coding
 sync:///Projects/KB
 sync:///FUNCTREE/ReuseMethodology/Clocking_Structure
 sync:///Projects/KB
 sync:///FUNCTREE/ReuseMethodology/Clocking_Structure
 sync:///Projects/Catalog
 sync:///Note/SyncNotes/Deliver/240
(323 rows)

-- This query aborts quite badly  --
syncdb=#  SELECT nl_obj_url FROM note_links_aux WHERE nl_obj_url LIKE
'sync:///FUNCTREE%' ;
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
The connection to the server was lost. Attempting reset: WARNING:  Message
from PostgreSQL backend:
        The Postmaster has informed me that some other backend
        died abnormally and possibly corrupted shared memory.
        I have rolled back the current transaction and am
        going to terminate your database system connection and exit.
        Please reconnect to the database system and repeat your query.
Failed.

*****************************
If I take oyut 'analyze' and run vacuum only, this problem never happens.
And this is fairly reproducable.

Is there any patch for this? Is this a known problem?
Thank you,
Mike.